These tips are very important and universal:
Sign at the back of your card on signature panel as soon as you receive it!
When you use your card at an ATM, enter your PIN in such a way that no one can see/understand/memorize your keystrokes.
Don't leave your receipt behind at the ATM. Your PIN and account number from a discarded receipt could make you exposed to credit-card fraud. Also, don't throw out your credit-card statement, receipts or carbons without first shredding them!
Never give your credit-card number over the telephone unless you initiated the call to the right destination.
Always ignore any credit-card offer that requests you to spend money first or fails to disclose the identity of the card issuer.
Make certain you get your card back after you make a purchase and it is used always in front of you. (it is very good habit to keep your wallet open in your hand until you take the card back). Also, please make sure that you personally rip up any voided or cancelled charge slips.
Always keep a list of your credit cards, credit-card numbers and call center numbers handy, in case your card is stolen or lost.
Check your monthly statement to make sure that all charges are of your own, and notify the card issuer of any errors or unauthorized charges immediately.